TOC | Pulm | ID    


Pertussis                                                See also  Bronchitis.htm                                 

Description:  Paroxysmal cough, acute tracheobronchitis

Whooping cough
Organism:  Bordetella pertussis (B. pertussis)  - small fastidious gram-negative bacillus  

-  up to 25% coughs lasting > 1 week have been attributed to pertussis (Arch Intern Med 1991 Aug;151(8):1510)

-  transmitted by droplets (airborne spread of respiratory secretions)

-  incubation period 5-21 days (commonly 7 days, rarely > 10 days)

Recommended exclusion period from school

  • if treated, 5 days from starting antibiotics, based on moderate evidence (well-designed study with 5-50 subjects)
  • if untreated, at least 3 weeks, based on moderate evidence (well-designed study with 5-50 subjects)
  • exclusion will not be fully effective because asymptomatic infections occur and may be involved in transmission
  • most children are protected by routine immunization (young children should be protected by routine immunization but immunity wanes in later childhood)

Diagnosis of Pertussis

Only pertussis diagnostic tests that are accepted to confirm a case for purposes of national reporting are culture and PCR (when the clinical case definition also is met)

Clinical case definition

  • hacking coughs with copious mucus, frequently mild or subclinical in adults, whoops, posttussive emesis  
  • cough illness lasting over 2 weeks
  • any of paroxysms of coughing, inspiratory "whoop" or posttussive vomiting  
  • 3 classic stages of illness are catarrhal, paroxysmal and convalescent (South Med J 1998 Aug;91(8):702   in QuickScan Reviews in Fam Pract 1999 Feb;23(11):13)
  • without other apparent cause (per healthcare provider)

Laboratory criteria for diagnosis

  • isolation of B. pertussis from clinical specimen
  • positive Polymerase chain reaction (PCR) assay for B. pertussis  
    - most sensitive diagnostic test, highly specific, but not FDA approved
    - polymerase chain reaction (PCR) should be the current diagnostic standard for diagnosis of pertussis
    - PCR more sensitive than culture in nasopharyngeal specimens in study of 376 patients using serologies as gold standard (Pediatrics 2000 Mar;105(3):e31)
  • nasal swab using synthetic tip in place for 10 seconds
  • culture and serology have also been used

Case classification


  • acute cough illness of any duration associated with B. pertussis isolation, or
  • case that meets clinical case definition and confirmed by PCR, or
  • case that meets clinical case definition as is epidemiologically linked directly to a case confirmed by culture or PCR

probable - case that meets clinical case definition, is not laboratory confirmed by culture or PCR, and is not epidemiologically linked to laboratory-confirmed case

Reference - MMWR Recomm Rep 2008 May 30;57(RR-4):1  


  • encephalopathy (anorexia, exhaustion)
  • pneumothorax
  • secondary bacterial pneumonia
  • family illness burden may warrant booster immunizations for adolescents and adults, based on study of 69 families (Arch Fam Med 2000 Nov-Dec;9(10):989 full-text)

Differential Diagnosis consideration: most patients with prolonged cough have

  • viral illness
  • asthma
  • chronic bronchitis
  • gastroesophageal reflux disease (GERD)
  • Mycoplasma pneumoniae
  • Chlamydia pneumoniae

Treatment overview:

Antibiotics recommended for infection control

  • azithromycin (Zithromax) 500 mg (10 mg/kg) once then 250 mg (5 mg/kg) once daily for 4 days; use 10 mg/kg/day for 5 days in infants < 6 months old
  • clarithromycin (Biaxin) 500 mg (7.5 mg/kg) twice daily for 7 days, not recommended for infants < 1 month old
  • erythromycin 500 mg (10-12.5 mg/kg) four times daily for 14 days, not recommended for infants < 1-6 months old
  • alternative is trimethoprim-sulfamethoxazole 160/800 mg (4/20 mg/kg) twice daily for 14 days, contraindicated in infants < 2 months old

Antibiotics may not change clinical course of pertussis but appear effective for microbiologic eradication .



Acute Bacterial Bronchitis Rx
  • Amoxicillin 500mg tid
    -All S.pneumoniae, many H.influenzae that do not produce B-lactamase. 
  • Augmentin (Amoxacillin/clavulanate) 500mg tid
    -All S.pneumoniae, H.influenza, Moraxella catarrhalis.
  • Erythromycin 500mg or EES 400mg qid
    -S.pneumoniae, M.catarrhalis, Mycoplasma, Chlamydia pneumoniae, Legionella sp. 
  • Azithromycin  (Zithromax) 250 mg 2 tab, then 1/day for total of 5 days
    -Chlamydia trachomatis, H.influenzae, Legionella sp., Moraxella catarrhalis, Mycoplasma pneumoniae,  S.aureus, Streptococcus pygenes
    -Campylobacter jejuni, Chlamydophilia pneumoniae, Hemohilus ducreyi (chancroid), Salmonella typhi, Shigella sp.
  • Clarithromycin (Biaxin) 500 mg bid x 1 week.                  
  • Cefaclor/Ceclor 500mg tid
  • Cefixime/Suprax 400mg qd
  • Cefuroxime/Ceftin 500mg bid
  • Ciprofloxacin/Cipro 500mg bid
    -H.influenza, M.catarrhalis, S.pneumo.
  • Doxycycline/Vibramycin 100mg bid
    -All except a small number of S.pneumo & H.influenza.
    -Moraxella caratthalis, Mycoplasma pneumonaie, Ricketssiae sp., Streptococcus anerobic, Vibrio cholerae,  Campylobacter jejuni, Chlamydophilia pneumoniae, Chlamydia trachomatis, Clostridium perfringens, Clostridium tetani, Tetanus, Q-fever, Tularemia.
  • Septra (Sulfamethoxazole/trimethoprim) DS bid
    -95% of S.pneumo, H.influenza, M.catarrhalis.


Diff-Dx of Acute Exacerbation of Chronic Bronchitis (AECB)
  • Bacterial bronchitis:
    - Common organisms: Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis.
    _ Less common organisms: gram-negative bacteria as Pseudomonas aeruginosa; Staphlococcus aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae
  • Viral bronchitis
  • Community-acquired pneumonia
  • Allergic or chemical tracheobronchitis
  • Congestive heart failure
  • Bronchospasm, including that induced by GE reflux
  • Pulmonary embolus
  • Pneumothorax


Antibiotic Rx Options for Acute Exacerbation of Chronic Bronchitis (AECB)
  1. Azithromycin or clarithromycin, new cephalosporins (cefpodoxime, defuroxime, cefprozil), doxycycline
    -for simple AECB (any age, <4x/yr, no comorbid illness)
    -likely pathogens: core organisms & H.parainfluenzae.
  2. Fluoroquinolones as Cipro, or amoxicillin+clavulanate (Augmentin)
    -for complicated AECB (age>65, >4x/yr, + comorbid illness)
    -likely pathogens: core organisms, but often drug-resistant pneumococci or B-lactamase-producing H.influenzae or M. catarrhalis; also some risk for enteric G-negative bacteria.
  3. Quinolone with antipseudomonal activity (Ciprofloxacin)
    -for complicated AECB at risk for Pseudomonas aeruginosa